Avalanche Forecast

Issued: Jan 18th, 2016 8:30AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Persistent Slabs and Wind Slabs.

Avalanche Canada pgoddard, Avalanche Canada

A touchy persistent slab problem demands respect. Use extra caution in your terrain selection.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Generally benign weather is expected for the next three days. Overnight Monday: 5-10 cm snow; Tuesday/ Wednesday: flurries; Thursday: 5-10 cm. The freezing level drops to valley floor late on Tuesday. For more details check out http://www.avalanche.ca/weather.

Avalanche Summary

Initial reports from Monday suggest a very sensitive persistent slab now exists in the Valemount area. A size 2.5 avalanche failed naturally, and skiers triggered wind loaded slopes at around 2100 m, which failed on the buried surface hoar. Skiers also remotely triggered a slab from 50 m away at 1300 m.In other areas, the persistent slab is also very easy to trigger where it is sitting on a widespread layer of surface hoar. We had a recent report from the Wells Grey area of a skier remotely triggering a size 2 avalanche that was 35 cm deep from 20 m away. This avalanche was 80 m wide and released on buried surface hoar in the alpine. This group also reported numerous whumpfs during the day.

Snowpack Summary

20-50 cm of recent storm snow has now formed a reactive slab over a volatile layer of buried surface hoar. The buried surface hoar may be most prevalent at and below treeline. The slab is likely to be especially reactive where it has gained cohesion through wind pressing, warming, and/or settlement. In general, the mid and lower snowpack are strong with any weak layers considered dormant for now. Snowpack depths are variable and shallow snowpack areas may have weak facetted crystals near the ground.

Problems

Persistent Slabs

An icon showing Persistent Slabs
Recent storm snow has formed a volatile slab where it overlies buried surface hoar. Avalanches may be triggered remotely and be surprisingly large.
Avoid steep open slopes and convex rolls at and below treeline where buried surface hoar may be well preserved.>Use conservative route selection.>Extra caution required in open terrain features below treeline.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Wind Slabs

An icon showing Wind Slabs
Wind slabs are extra touchy where they overlie buried surface hoar.
Travel on ridgetops to avoid wind slabs on slopes below.>Avoid lee and cross-loaded terrain near ridge crests.>

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Jan 19th, 2016 2:00PM

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